ISRO Scientist or Engineer Computer Science Dec 2017

Instructions

For the following questions answer them individually

Question 11

Consider the schema
Sailors(sid, sname, rating, age) with the following data

For the query
SELECT S.rating, AVG(S.age) AS avgage FROM Sailors S
Where S.age $$\ge$$ 18
GROUP BY S.rating
HAVING 1 $$<$$ (SELECT COUNT($$*$$) FROM Sailors S2 where S.rating $$=$$ S2.rating)
The number of rows returned is

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Question 12

Consider a table that describes the customers :
Customers(custid, name, gender, rating)
The rating value is an integer in the range 1 to 5 and only two values (male and female) are recorded for gender. Consider the query “how many male customers have a rating of 5”? The best indexing mechanism appropriate for the query is

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Question 13

Consider the following schema :
Sailors(sid,sname,rating,age)
Boats(bid,bname, colour)
Reserves(sid,bid,day)
Two boats can have the same name but the colour differentiates them.
The two relations
$$\rho(Tempsids, (\pi_{sid, bid}Reserves)/(\pi_{bid }(\sigma_{bname = 'Ganga'} Boats)))$$,
$$\pi_{sname}(Tempsids \bowtie Sailors)$$
If / is division operation, the above set of relations represents the query

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Question 14

Type IV JDBC driver is a driver

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Question 15

Consider the following table : Faculty(facName, dept, office, rank, dateHired)

(Assume that no faculty member within a single department has same name. Each faculty member has only one office identified in office). 3NF refers to third normal form and BNCF
refers to Boyce-Codd normal form
Then Faculty is

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Question 16

Consider the following query :
SELECT E.eno, COUNT(*)
FROM Employees E
GROUP BY E.eno
If an index on eno is available, the query can be answered by scanning only the index if

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Question 17

If C is a skew-symmetric matrix of order n and X is $$n \times 1$$ column matrix, then $$X^T CX$$ is a

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Question 18

Consider the recurrence equation
$$T(n) = \begin{cases}2T(n - 1), & if n> 0\\1 & otherwise\end{cases}$$
Then T(n) is (in big O order)

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Question 19

Consider the program
void function (int n) {
int i, j, count = 0;
for (i = n/2; i <= n; i++)
for (j = 1; j <= n; j = j * 2)
count++;
}
The complexity of the program is

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Question 20

Match the following and choose the correct answer for the order A,B,C,D

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